wet sanding?

I have heard this term used many times when people describe how they painted their cars.. i was just wundering what exactly "wet sanding" is it, how to do it, and when to do it.. im just about to paint my gto tamiya mitallic blue and thought i'd give the wet sanding a shot... thanks for the help

On 8/31 there was a thread on the same topic.

http://www.automotiveforums.com/vbulletin/showthread.php?t=451838

thanks